Switch for flash attachments



Jan, 24, 1950 J. P. CASTELLANO SWITCH FOR. FLASH ATTACHMENTS Filed Nov. 25, 1947 W INVENTOR Jbseph l? C'asiellano Q l BY W aATToRNEYs Patented Jan. 24, 1950 SWITGH FOR-FI3ASH"ATTAGH1\IENTS J oseph. B..Castellano; Brooklyn, N; Y.', assignor.: to Norman.Nel'son.Cor.p;., New. York,.N..Y., a-.. corporationofNewiYork ApplicationrNovember 25, 19147; Serial'Nir787,905

4. Claims. (Cl. 2009-81-9) The present invention relates to newanduseful improvements in photographic flash: guns, and more particularly to a slow-speed synchronizer foruse with studio shutters;

Objects and advantages of the invention will be set forth in part hereinafter and in. partiwill be obvious herefrom, or maybe learned by practice with the invention, the same being realizedand attained by meansof the instrumentalities and combinations pointed out in the-appended claims;

The,inventionconsists-in the novelparts, cone structions, arrangements; combinations, and ima provements herein shown and described.

The accompanyingdrawings, referred toherein and constituting a parthereof, illustrate one em.- bcdiment of the invention, and together withthe description, serve to explainthe-principlesof: the invention.

Of the drawings:

Figure 1 is aview, partly inpsection andpartly schematic of .the present preferred and illustrativeembodiment of. the; present invention; 1 and 2 FigureZ is a detailedicrosssection.takenon the line 2--2 of Figureli The. present. inventionv has; for' its object the:

provision of ,a simple, efficient, easily'manufaca tured and reliable flashlight synchronizing switch particularly adapted for use: with, pneumatic studio shutters which are usuallyof .relativel-yislow operation. A further; object of theainventioniis the provision of. an improved flashlight synchroe nizing switch: which allows the. shutter to; be

which the shutter is closed. When the camera'is.

ready'for exposure, theshutter to be opened and the flash should occur only'duringthissec- 0nd opening of the shutter. By the use of the present invention the flashlight apparatus may be completely readied for use before the first opening of the shutter, but is not fired until the shutter is opened for exposure.

In accordance with the preferred embodiment of the invention, the flashlight synchronized switch is interposed in the pneumatic connection between thezshutter: and. its"v actuating bulb, and this switchcomprisesa contact memberadapted to; be: movedto; circuitrclosing positioniby a rapid change in pressurein. the. pneumatic tube, but

alsoi adaptedlto remaininopen. circuit position when the change in pressure: in' the pneumatic tube is; less rapid-but nevertheless sufficient. to efiect; opening oiithe. camera shutter.

It wil1..be. understoodj'that the foregoing general description and the following detailed description as wellv are, exemplary and, explanatory of" the invention but are notirestri'ctivethereof.

Referring: now in detailito the present preferred and illustrative embodiment of: the invention as showniin' the accompanying drawings; the camera shutter- 19 .is. of conventional construction; and may be,.-any pneumatically actuated I shutter, and is. connectediwithtthe usual aair bulb a l 2 by means of. the flexible pneumatic. tube. 14 so that squeeze ing; the bulb; l2 lcausesioperationrof the. pneumatic motonl'fi to openthe shutter, while release ofthe bulb. 12.;allows the. shutter to. close. Interposed betweemthe ends-of thepneumatic tube i4 is the flashlight. synchronizing-switch .2 0. of, the present i invention which is connected. between the battery z2f and therfiashwbulb 24. Battery 22 andiflash hulb24 are shown inra-purely diagrammatic mannerandzrnaysbezof any desired construction.

The synchronized switch 20 is preferably formedinitwo: parts-126., 2 1 of insulatingmaterial such as a synthetic resin... Onev of the parts 26 is. provided with .arlongitudinalpassageway 28 fromithevendswof which extend-short, rigidtube ends 29 andz38 over which :the ends of the flexible airtight tube It maybe slippedto; form anair inairtight:relation-by means of screw- 36 passing through the part 2-1 and threaded into part 2'6; andby a; metallic; contact screw' 38which is pro- .vided with lock nut 39 passing through block 21 and has a reduced threaded portion 40 threaded into the block 26. Screw 38 also serves to firmly locate a relatively thin and flexible spring contact 42 which extends into the chamber 34 and normally rests against the flat surface 33, thereby closing the aperture 32.

The flexible spring contact 42 is preferably in the form of a leaf spring and is notched near the point where it enters the chamber 34, as at 43, to increase its flexibility. While this spring may be made of various materials, it is preferably made of material having good spring characteristics and good electrical conductivity such as Phosphor bronze.

Alined with the aperture 32 and extending into the chamber 34, in a position where it may be contacted with the leaf spring 42, is an adjustable contact 46 locked in position by lock nut 4'1 having its exterior threadedly engaged in corresponding threads in the member 21. Screw threaded member 46 is provided with an axially extending aperture 48 which extends to both ends of the member 46, and provides a bleed duct bleeding the internal chamber 34 to the outside. Normally, and as shown, the internal end of screw member 46 is spaced from the face of leaf spring 42 a substantial distance, but not so much as to prevent contact of the leaf spring 42 with the internal end of the screw member 46, and when so contacted leaf spring 42 closes the inner end of the central bore 48 so as to prevent substantial leakage of air through this bleed duct.

Preferably the bores of apertures 32 and 48 are substantially equal, and are both much smaller than the diameter of the passageway 28 from which they receive their flow of air. The

strength of spring 42 is such that an increase of air pressure within the passageway 28 more than suflicient to open the shutter, is required to unseat the leaf spring 42 from the flat seat 33 surrounding the aperture 32, thereby permitting the motor 16 to be actuated with certainty without movement of the leaf spring 42. However, leaf spring 42 is not so stiff, and the distance normally spacing it from the internal end of screw member 46 is not so great but that a sudden, large increase in the pressure within passage 28 will move the leaf spring 42 into contact with screw member 46, thereby establishing an electric circuit between the screw members 38 and 46, these members serving as the terminals of the switch in series with the flash bulb 24 and battery 22. When the leaf spring 42 is seated against the internal end of the screw member or contact 46, it closes the bore 48 thereby preventing escape of air from the chamber 34 and accordingly preventing accidental closure of the shutter before the bulb I2 is released.

The invention thus provides a switch mechanism in which the movable contact is not moved to circuit closing position except on a sudden large increase in pressure in the duct 32, at least suflicient to move the leaf spring 42 against the contact screw 46. This movement seals duct 48 and the pressure in duct 32 is then transferred to the chamber 34 serving to hold the leaf spring 42 seated in contact with the screw 46 to close duct 48, so that good electrical contact is established and leakage of air from the passage 28 is prevented.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims 4 without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. In a shutter synchronizing switch for photographic flash lamps, the combination of a passageway subject to increased fluid pressure when the shutter is to be opened, a restricted duct communicating with said passageway, a switch contact and a movable contact engageable with the first contact to close a circuit, the movable contact being normally in open circuit position and urged to close said duct, said switch contact being formed with a bleed duct to be closed by movement of the movable contact to circuit closing position.

1 2. In a shutter synchronizing switch for photographic flash lamps, the combination of a switch body, an air passage therethrough, an air chamber in said body closed except for a restricted duct connecting the passage with the chamber and a bleed duct connecting the chamber to atmosphere, a movable contact member in said chamber normally closing said restricted duct, and a fixed contact to be engaged by said movable contact when moved by air issuing through said restricted duct, said movable contact closing said bleed duct when engaged with said fixed contact.

3. In a shutter synchronizing switch for photographic flash lamps, the combination of a switch body, an air passage therethrough, an air chamber in said body, a restricted duct connecting the passage with the chamber, a movable contact member in said chamber and normally closing said duct and a fixed contact to be engaged by said movable contact when moved by air issuing through said duct, said fixed contact having an aperture therein to bleed air from the chamber, said aperture being closed by said movable contact when engaging said fixed contact.

4. In a shutter synchronizing switch for photographic flash lamps, the combination of a switch body, an air passage therethrough, an air chamber in said body, a restricted duct connecting the passage with the chamber, a movable contact member in said chamber and normally closing said duct and a fixed contact to be engaged by said movable contact when moved by air issuing through said duct, said fixed contact having an aperture therein to bleed air from the chamber, said aperture being closed by said movable contact when engaging said fixed contact, said duct and aperture being alined and positioned on opposite sides of said movable contact.

JOSEPH P. CASTELLANO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 828,262 Adams Aug. 7, 1906 1,076,091 Allen Oct. 21, 1913 2,153,277 Sharp Apr. 4, 1939 2,173,370 Parachek Sept. 19, 1939 

